 
(* ::Section:: *)
(* SFAD *)
(* ::Text:: *)
(*SFAD[{{q1 +..., p1 . q2 +...,} {m^2, s}, n}, ...] denotes a Lorentzian propagator given by 1/[(q1+...)^2 + p1.q2 ... + m^2 + sign*I*eta]^n, where  q1^2 and p1.q2 are scalar products of Lorentz vectors in D dimensions. For brevity one can also use shorter forms such as SFAD[{q1+ ...,  m^2}, ...], SFAD[{q1+ ...,  m^2 , n}, ...], SFAD[{q1+ ...,  {m^2, -1}}, ...], SFAD[q1,...]  etc. If s is not explicitly specified, then its value is determined by the option EtaSign, which has the default value +1. If n is not explicitly specified, then the default value 1 is assumed. Translation into FeynCalc internal form is performed by FeynCalcInternal, where a SFAD is encoded using the special head StandardPropagatorDenominator..*)


(* ::Subsection:: *)
(* Examples *)
SFAD[{{p,0},m^2}]

SFAD[{{p,0},{m^2,-1}}]

SFAD[{{p,0},{-m^2,-1}}]

SFAD[{{0,p.q},m^2}]
